Unitary breechblock assembly

ABSTRACT

A single-shot break action firearm includes a receiver, a barrel, and a stock. The receiver has a breach portion that defines a cavity that is sized and shaped to house a breechblock therein. The breechblock is constructed from a powdered metal formed by metal-injection-molding. The breechblock is form from a higher strength material than the receiver to contain explosive forces produced during discharge of the firearm. The barrel is connected with the receiver and extends forward therefrom. The stock is connected with the receiver and extends rearward therefrom.

CROSS REFERENCE TO RELATED APPLICATION

room This application claims the benefit of U.S. Provisional ApplicationNo. 61/367,950, filed Jul. 27, 2010, entitled “UNITARY BREECH BLOCKASSEMBLY”, the aforementioned application being hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to firearms and, more particularly, tosingle-shot break action firearms.

BACKGROUND OF THE INVENTION

Single-shot break action firearms, typically, have a barrel enclosing abore that extends from a breech end to a muzzle end of the barrel. Thebarrel is pivotally mounted to a receiver disposed near the breech endof the barrel. The receiver includes a breechblock, which blocks thebreech end of the barrel when the barrel is in a closed position.Pivoting motion of the barrel on the receiver shifts the barrel to anopen position wherein the breechblock does not block the breech end ofthe barrel. The breechblock typically houses a firing pin, which isaligned with an inner diameter of the barrel bore when the barrel isclosed. The receiver typically houses a pivotally movable hammer and atrigger, by which the firing pin may be actuated toward the muzzle endof the barrel when the barrel is closed. Typical firearms also includeergonomic parts, such as a stock and a fore end, which are attached tothe receiver. Typical break action firearms further include some sort ofmechanism for securing the barrel in the closed position.

For loading the typical break action firearm, the barrel opened and asingle cartridge of ammunition is inserted into the breech end of thebarrel with the bullet toward the muzzle end of the barrel and with theprimer rim fitted snugly to the breech end. The barrel then is closed.For firing, the trigger is pulled to release the hammer, which drivesthe firing pin forward against the primer rim of the cartridge,discharging the round down the bore.

Break action firearms typically are marketed either as economicalsporting goods, or as finely crafted works of gunsmithing. In agunsmithed break action firearm, all of the metal parts including thereceiver and the firing mechanism are forged and machined from highquality materials such as steel. The use of high quality materials andtime-intensive manufacturing processes results in high costs. On theother hand, for casual sporting firearms, it is common to economize onmaterials and modes of manufacture. In particular, the receiver of abreak action firearm typically is die cast, with moving parts such asthe hammer and trigger being pivoted on pins pressed through thereceiver.

One potential problem with economical firearms is that the breechblockportion of the receiver can become worn by pivoting motion of thebarrel. This wear, in turn, may adversely affect the performance ofcartridges—for example, by permitting the rim of a cartridge to shift inthe gap between the breechblock and the breech end of the barrel.

Accordingly, there is a need for an economically manufactured singleshot firearm, in which the wear parts are formed from high qualitymaterials at low cost, while non-moving parts are cast from lower costmaterials.

SUMMARY OF THE INVENTION

According to the present invention, a firearm receiver is die cast atlow cost and is adapted to receive a slide-in unitary breechblock andbarrel catch assembly, which provides sturdy wear surfaces at minimalcost of manufacture.

Additionally, upper interior surfaces of the die cast receiver aremachined to provide interference flats, which engage complementary flatsformed on a barrel tang, thereby enhancing engagement of the barrelcatch with the barrel tang.

Additionally, the barrel tang, barrel catch, trigger, and hammer aremutually positioned to provide an interlock that prevents closing thebarrel with the hammer cocked, and that also prevents releasing thehammer unless the barrel is fully closed or fully opened.

These and other objects, features and advantages of the presentinvention will become apparent in light of the detailed description ofthe best mode embodiment thereof, as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of a break action firearm according to anembodiment of the present invention.

FIG. 2 shows a left side sectional assembled partial view of a receiver,barrel assembly, catch mechanism, and firing mechanism of the firearmshown in FIG. 1, with the barrel assembly in a closed position.

FIG. 3A shows a left side view of the firing mechanism without thereceiver of the break action firearm shown in FIGS. 1 and 2.

FIGS. 3B shows a left side view of the receiver without the firingmechanism of the break action firearm shown in FIGS. 1 and 2.

FIG. 4 shows a front exploded view of the break action firearm shown inFIGS. 1 through 3.

FIG. 5 shows a perspective exploded view of the firearm shown in FIGS. 1through 4.

FIG. 6 shows a right side sectional exploded view of the receiver, catchmechanism, and firing mechanism shown in FIG. 2.

FIG. 7 shows a forward partially exploded view of the firing mechanismand the barrel catch mechanism shown in FIGS. 1 through 6.

FIG. 8 shows a right side sectional exploded view of the firingmechanism and the barrel catch mechanism shown in FIGS. 1 through 7 in apartially open position.

FIG. 9 shows a top perspective view of the receiver shown in FIGS. 1through 7.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, a break action rifle 10 includes a barrel 12, whichis pivotally mounted to a receiver 14 that supports a fore end 16 and astock 18. The receiver also houses a firing mechanism 20, of which ahammer 22 and a trigger 24 are shown in FIG. 1, and a catch mechanism 66(shown in FIG. 2). The barrel 12 has a breech end 26 and a muzzle end28.

Referring to FIG. 2, the barrel 12 is connected to the receiver 14 byway of a barrel tang 30 and a pivot pin 32, located near the barrelbreech end 26. The barrel tang 30 is attached to the barrel 12 by bolts34 threaded into holes 35 tapped into the outer surface of the barrel12. The barrel tang 30 includes a transverse through hole 36, while thereceiver 14 includes transverse holes 38. The pivot pin 32 is insertedthrough the transverse holes 36, 38 to pivotally mount the barrel 12 tothe receiver 14. The barrel 12 is pivotal between a closed position,where the breech end 26 rests against a breech portion 40 of thereceiver 14, and an open position, where the breech end 26 is raisedaway from the receiver 14 permitting access to the barrel bore 41, asshown in FIG. 8.

With additional reference to FIGS. 5 through 7, the breech portion 40 ofthe receiver 14 houses a breechblock 42. When the barrel 12 is in theclosed position, the breechblock 42 secures a cartridge 43 into thebreech end 26 of the bore 41. The receiver 14 may be die cast from basemetal or even from a thermoset plastic or fiber-resin composite.However, the breechblock 42 is injection-molded from high quality metal(such as steel powder) to form a high-strength, temperature- andwear-resistant structure suitable for containing the explosive forcesproduced by discharge of a rim fire rifle cartridge 43. In addition toenhanced strength over what can be achieved by die casting,metal-injection-molding (MIM) offers dimensional tolerances approachingwhat can be achieved by machining stock metal, so that MIM parts do notrequire the same level of finish machining as do conventionally die-castparts. Thus, the separate structures of the receiver 14 and of thebreechblock 42 offer optimal strength and fit at the critical locationsurrounding the breech end 26 of the barrel 12, with lower cost ofmanufacture than can be achieved by machining the receiver 14 andbreechblock 42 as a single piece.

The breechblock 42 houses a firing pin 44 and a firing pin spring 46,which are parts of the firing mechanism 20. The firing pin 44 ispositioned to be driven forward by the hammer 22, which is forwardlybiased around a hammer pin 48 by a hammer spring 50. When the hammer 22is pulled back to a cocked position, the trigger 24 is biased rearwardaround a trigger pin 52 by a trigger spring 54 so that a sear fingerportion 56 of the hammer 22 engages a cocking notch 58 formed on the topend 25 of the trigger 24, thereby restraining the hammer 22 in thecocked position. By pulling the finger part 60 of the trigger 24rearward, a shooter can release the hammer 22 to drive the firing pin 44forward against the rim of a cartridge 43 loaded into the barrel bore41.

Additionally, the breechblock 42 includes laterally extending pivots 62,which support a barrel catch 64 that is part of the catch mechanism 66mentioned above. The barrel catch 64 is forwardly biased around thepivots 62 by a catch spring 68, which presses downwardly against a heel70 of the barrel catch 64 to push the barrel catch 64 into a notch 72formed in the rearward part of the barrel tang 30. Engagement of thebarrel catch 64 into the notch 72 of the barrel tang 30 secures thebarrel 12 in the closed position. The catch mechanism 66 also includes atrigger guard 74, which is pivotally mounted on a transverse pin 76, anda guard spring 78 with one end fastened to the receiver 14. The otherend of the guard spring 78 rests against an inner surface 80 of thetrigger guard 74 to downwardly bias the trigger guard 74 around thetransverse pin 76. When a shooter pulls the trigger guard 74 rearwardand upward against the guard spring 78, an upper finger 82 of thetrigger guard 74 pushes upward on the heel 70 of the barrel catch 64 torelease the barrel catch 64 from the barrel tang 30, thereby permittingthe barrel 12 to pivot to the open position.

Referring briefly to FIG. 8, it can be seen that when the barrel 12 isopened, a knuckle 73 formed on the barrel tang 30 presses the barrelcatch 64 rearward against the trigger 24. In case the hammer 22 iscocked when the barrel 12 is opened, pressure of the barrel catch 64against the trigger 24 captures the sear finger portion 56 into thecocking notch 58, so that the trigger 24 cannot be pulled rearward torelease the hammer 22. Thus the cocked weapon cannot be dischargedunless the barrel 12 is fully closed; alternatively, the hammer 22cannot be decocked unless the barrel 12 is fully opened. This interlockaverts discharging a loaded cartridge with the barrel 12 less than fullylatched closed.

Referring briefly to FIG. 9, the barrel tang 30 includes protruding sideposts 83 with flattened lower faces 85. When the barrel 12 is fullyclosed, the lower faces 85 of the side posts 83 rest againstcomplementary flats 87 machined into the receiver 14. The barrel catch64 wedges into the notch 72 of the barrel tang 30 to firmly seat thecomplementary flats 87 together, and the opposed flats reciprocally pushthe notch 72 upwards to maintain the barrel catch 64 firmly engaged.

Referring back to FIG. 2, between the barrel 12 and the barrel tang 30,an extractor 84 is captured on the bolts 34. The extractor 84 includeslongitudinal slots 86 (better shown in FIG. 3A) for receiving the bolts34 so that the extractor 84 can slide lengthwise along the barrel 12between forward (retracted) and rearward (extended) positions when thebarrel 12 is pivoted to the opened position, as further explained below.

Referring to FIGS. 3A through 4, the receiver 14 encloses an actioncavity 88 housing the firing mechanism 20 and the catch mechanism 66, abarrel tang slot 89 for receiving the barrel tang 30, and a breechcavity 90 for receiving the breechblock 42. For assembly of the hammer22 and the trigger 24, the receiver 14 includes pinholes 92 and 94,respectively, as well as a hammer slot 93 and a trigger slot 95. Forassembly of the catch mechanism 66 into the receiver 14, the receiver 14also includes a catch spring groove 96, lateral pivot grooves 98, aguard spring groove 100, a guard recess 102, a guard pinhole 103, and abreech bolt hole 104. The breechblock 42 is fastened to the receiver 14by a breech bolt 106 threaded into the breechblock 42 via the breechbolt hole 104. For operation of the extractor 82, the receiver 14 alsoincludes a camming surface 108 offset from the pivot pin 32 at theforward end of the receiver 14. When the barrel 12 is pivoted to theopen position, the forward end of the extractor 84 contacts the cammingsurface 108 so that the extractor 84 is pushed rearward to pull thecartridge 43 out of the breech end 26 of the bore 41. For assembly ofthe stock 18, the receiver 14 also includes a stock bolt hole 110.

In addition to the breechblock 42, the hammer 22, the trigger 24, thefiring pin 44, the barrel catch 64, and the extractor 82 preferably aremetal-injection-molded for enhanced dimensional accuracy and durability.

Opposite the barrel tang 30, a sight mount 111 is fixed to the upperside of the barrel 12 by screws 112 threaded into tapped holes 113. Thesight mount 111 also can be metal-injection-molded, or can be die cast.

The fore end 16 is fastened to the barrel 12 by bolts 113, while thestock 18 is fastened to the receiver 14 by a single large bolt 114. Thestock 18 includes an aesthetic cap 116 snapped over the large bolt 114,and also includes a shock-absorbing butt piece 118, which is secured tothe stock by screws 120.

One advantage of the present invention is that the pre-assembledbreechblock and catch ensure proper alignment of the catch with thenotch formed in the barrel tang. Also, the pre-assembled breechblock andcatch reduce the number of holes that must be formed at mutuallyaccurate positions in the receiver. The catch spring and guard springgrooves further simplify assembly of the catch mechanism relative topreviously known designs.

Although this invention has been shown and described with respect todetailed embodiments thereof, it will be understood by those skilled inthe art that various changes in form and detail thereof may be madewithout departing from the spirit and the scope of the invention.

1. A single-shot break action firearm comprising: a receiver having abreech portion, the breech portion defining a cavity being sized andshaped to house a breechblock therein, the breechblock being constructedfrom a powdered metal formed by metal-injection-molding, the breechblockbeing constructed of a higher strength material than the receiver tocontain explosive forces produced during discharge of the firearm; abarrel connected with the receiver and extending forward therefrom; anda stock connected with the receiver and extending rearward therefrom. 2.The single-shot break action firearm according to claim 1, furthercomprising at least one moveable component housed within the receiverand constructed from a powdered metal formed by metal-injection-molding,the at least one movable component being selected from the groupconsisting of a hammer, a trigger, a firing pin, a barrel catch, and anextractor.
 3. The single-shot break action firearm according to claim 1,further comprising a sight mount constructed from a powdered metalformed by metal-injection-molding, the sight mount being attached to thetop of the barrel by screws that extend into the barrel.
 4. Thesingle-shot break action firearm according to claim 1, wherein thebreech block is pivotally connected with a barrel catch to form aslide-in unitary breech block and barrel catch assembly, the receiverbeing formed by die cast, the receiver being sized and shaped to receivethe slide-in unitary breech block and barrel catch assembly.
 5. Thesingle-shot break action firearm according to claim 1, wherein thereceiver houses a firing mechanism, the firing mechanism including afiring pin and firing pin spring clamped between the receiver and thebreech block.
 6. The single-shot break action firearm according to claim1, wherein the barrel is connected to the receiver by a barrel tang thatis bolted to the barrel and is pivotable with respect to the receiverand stationary with respect to the barrel.
 7. The single-shot breakaction firearm according to claim 6, wherein a pivot pin connects thebarrel tang with the receiver by extending through transverse holes inboth the receiver and the barrel tang, the barrel being void of a directconnection to the receiver.
 8. The single-shot break action firearmaccording to claim 6, wherein the upper interior surfaces of the diecast receiver being machined to provide interference flats thatcomplement flats formed on a barrel tang to enhance engagement of thebarrel catch with the barrel tang.
 9. The single-shot break actionfirearm according to claim 1, the receiver being constructed from amaterial selected from the group consisting of being formed from a basemetal that is die cast, being formed of a thermoset plastic, and beingformed of a fiber-resin composite.
 10. The single-shot break actionfirearm according to claim 1, wherein the powdered metal used toconstruct the breechblock being a steel powder.
 11. The single-shotbreak action firearm according to claim 1, the breech block beingconnected with the receiver with a breech bolt extending from the breechportion of the receiver into the breech bock.
 12. The single-shot breakaction firearm according to claim 1, wherein the breech block pivotallysupporting a barrel catch for retaining the barrel in a closed position,the barrel catch being void of any pivotal connections to the receiver.13. A receiver defining a cavity being sized and shaped to house abreechblock therein, the breechblock being constructed from a powderedmetal formed by metal-injection-molding, the breechblock beingconstructed of a higher strength material than the receiver to containexplosive forces produced during discharge of the firearm.